This invention deals generally with making sheet goods, and more specifically with the production of indefinite lengths of patterned sheet flooring product in widths much wider than are generally available.
The widths of decorative sheet flooring materials have generally been limited to about twelve feet because the machines which produce such flooring must be even wider than the product they produce, and twelve foot wide material is satisfactory for most applications. However, there is some demand for larger widths, and the demand appears to be increasing for such greater widths, particularly for the manufactured home industry.
Although some machines are built which produce greater widths, they are very large and expensive, and the capital cost is difficult to justify without a significant long range market for such extra width product. Furthermore, regardless of what greater width machine is selected, there may always be some market for product of even greater width.
The most obvious method of producing such wider product is simply to bond two or more narrow sheets together to form a wider sheet, but such a technique raises new problems. One problem is that the bond at which the narrow sheets meet usually has a slightly greater thickness than the adjacent product. Although this may not be a drawback during the actual use of the product on floors, since flooring is transported and sold in rolls, this slightly thicker seam causes a bulge on the roll where the seam is repetitively rolled up upon itself.
A more severe but subtle problem is the mismatching of patterns on two independently produced rolls of narrow material. Although the repetitive patterns on flooring material are reproduced accurately, stretching or shrinkage in the base material is not absolutely predictable, and it is virtually impossible to assure that patterns on the edges of two independently produced rolls of flooring material will exactly match over lengths of more than several feet. Therefore, while a seam running the full length between two narrow rolls of material may be barely perceptible once on the floor, the misalignment of two supposedly identical patterns over the length of the rolls will be so noticeable that a wider roll manufactured in such a manner is unusable.
Thus, until now manufacturers of patterned flooring who wanted to produce wider than usual product, had only one choice, that of purchasing a machine large enough to manufacture the width desired.